1. Field of the Invention
The invention relates to the field of aircraft and, in particular, to a system and method for landing an unmanned tailless or flying wing type aircraft in a crosswind.
2. Description of Related Art
Flying wing or tailless aircraft have a particularly unique problem. They have no vertical surfaces to provide a lateral force to control the effect of a crosswind during landings where the aircraft's flight path is at an angle to the longitudinal axis thereof. While the tailless aircraft can land flat, its wheels will strike the runway with a larger lateral offset than a conventional aircraft with vertical surfaces. The nose wheel is in front of the center of gravity (CG) and the side force generated by the wheel is very unstable. The offset in the angle means that when the aircraft touches down there will be a sudden lateral jerk in the direction the wheels are pointing. The resulting acceleration will cause one wing tip to dip or in a worst case, it can result in a ground loop.
U.S. Pat. No. 5,523,921 Aircraft Steering System And Method For Large Aircraft Having Main Landing Gear Steering During Low Taxi Speed While Nose Gear is Castored by H. C. Ralph discloses the concept of allowing the nose wheel to castor so that differential braking of the main landing gear can be used to turn the aircraft. The nose wheel landing gear includes a system to allow for turning with the nose wheel, but allows it to castor on command. The nose wheel steering system is described in Great Britain Patent No.: 879,279 Improvements Relating To Steering Mechanism For An Aircraft Ground Wheel Mounting by H. Cyril, et al. and is herein incorporated by reference.
Thus, it is a primary object of the invention to provide process to allow a tailless aircraft to land in a crosswind.
It is a further object of the invention to provide a process to allow a flying wing type aircraft to land in a crosswind by reducing the adverse effect at the moment of touchdown due to crabbing of the aircraft in a crosswind.